The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
In the construction and development of wells formed in subterranean formations, such as wells for the production of oil and gas, various operations are carried out that require the introduction of fluids of different types into the wellbore and/or into formation surrounding the wellbore.
Hydraulic fracturing is one such operation conducted in wells that is used to increase the production of fluids from the subterranean formations. Hydraulic fracturing involves introducing fluids into the wellbore at very high flow rates and pressures to facilitate cracking and fracturing of the surrounding formation. The fracturing fluid injection rate exceeds the filtration rate into the formation so that the pressure increases at the rock face. Once the pressure exceeds the fracturing pressure threshold of the rock, the formation cracks and the fracture begins to propagate as the injection of the fracturing fluid continues.
In hydraulic fracturing, generally a proppant is introduced into the formation with the fracturing fluids at certain stages of the fracturing operation. Typically, the proppant is admixed with the fracturing fluid continuously during the treatment. The proppant (e.g. sand) is deposited in the formed fractures of the formation so the proppant prevents the fracture from closing when the pressure is reduced. This allows reservoir fluids to flow from the formation through the fractures to the wellbore so that they can be produced. Various methods exist for fracturing such formations.
Recently, techniques have been developed to provide heterogeneous proppant placement in the fracture. While heterogeneous proppant placement in hydraulic fracturing is known, methods of providing proppant slugs in fracturing fluids to provide heterogeneous proppant placement within the fractures of the formation are still in need of development.